Prior vibrating screening apparatus, whether inclined or, as disclosed in the U.S. Pats. to Jacobson No. 3,905,897 ('897) and Johnson et al No. 4,632,751 ('751), horizontal, customarily has a frame forward of transversely spaced spring-mounted side frames connected by cross-members and has between the side frames either one or a plurality of parallel vertically spaced decks or beds for mounting woven or, now more usually, wedge or profile wire screens. The apparatus also includes vibrating mechanism, which at least in the horizontal type, ordinarily is mounted on the frame above the screen decks, as in Jacobson. Also, as in Jacobson, the cross-members may be crosstubes welded at their ends to end plates and bolted through the end plates to the side plates.
A problem with prior vibrating screening apparatus is that even when, as in Jacobson, the crosstubes are bolted to the side plates and support the screen decks, the longitudinally extending elements or members of the decks intermediate the side frames are welded at intersections to the crosstubes. Not only is relief of their residual stress practically impossible but the welds are not adapted to yield without fracture to the flexing of crosstubes in response to the flexing of the side frames on their springs under the forces applied by the counterweighted vibrating mechanism.
Consequent upon dependence on welds for connecting vital parts, prior vibrating screening apparatus not only are prone to parts fracture but repair or replacement of a fractured part is at least a difficult and often an impossible task. The concern of the present invention is in vibrating screening apparatus to drastically reduce the likelihood of parts fracture and permit and facilitate repair or replacement of individual parts.